(usr-tc) v.42bis problems
An old problem has just come back, but in only one weird case. I've got a crapload of people getting randomly bumped offline with v.42 or v.42bis related problems. (I suspect v.42bis.) However... it's only happening on the first 12 channels of ONE DSP card. It's not happening on the other 11 channels of that card, or of any other card in that city or any other city. The card is configured *identically* to the others in every way I can think of checking -- all DSP's are running 2.0.51, though they have varying hardware revisions. The card in question is revision 0.49. Just from midnight to 4:30 pm today on these 12 channels, I've had 310 disconnects for "v.42 string too long", 63 disconnects for "v.42 invalid codeword", and 17 disconnects for "Link security abort". It doesn't matter what brand of modem the client is calling in with. It could be a cheap Winmodem, it could be a USR Courier. It definitely happens with USR modems. For now I've disabled v.42bis on this card until I can figure out what's going on. Disabling v.42bis stops the disconnects. I seem to remember having this problem once quite a while ago, but it was more widespread then... it had popped up right after a DSP firmware upgrade (I think to 1.2.68 at the time). And this has popped up right after going from 2.0.60 to 2.0.51 -- but again, only on half of one card. Ideas? Mike Andrews (MA12) * mandrews@dcr.net * http://www.bit0.com/ VP, sysadmin, & network guy, Digital Crescent Inc, Frankfort KY Internet services for Frankfort, Lawrenceburg, Owenton, & Shelbyville "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
Anyone have a clue as to the correct ( if there is even such a thing ) settings on the dsp's. On all code previous to 2.0.51 the the default has been 11db. I have experimented with using a setting of 13db, 2 db lower power. Don't really know how this has affected the overall problem that i'm trying to solve of disconnects. I came to setting from trials with multitech analog modems. Changing from 11 to 13 on those solved a ton of problems. So i was surprised to see the default setting for 2.0.51 set to 10. What are you guys running or do you even bother setting these levels? - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
On Fri, 7 Jan 2000, Mike Andrews wrote:
An old problem has just come back, but in only one weird case.
I've got a crapload of people getting randomly bumped offline with v.42 or v.42bis related problems. (I suspect v.42bis.)
However... it's only happening on the first 12 channels of ONE DSP card.
I had a similar problem that turned out to be a DSP hardware problem. One of my DSP's would, after moderate use, not answer on the first 12 channels until it was reset. I had flashed several different versions of code, tried different lines (CT1 and PRI), different locations, chassis's, etc. Nothing made a difference. After jerking around with 3COM's RMA dept for a while (you can't RMA it until a tech says it's bad, you can't talk to a tech without a contract) my vendor offered to RMA it for me. I have not seen this symptom pop up on any other cards I have. -- Horace Demmink PathWay Computing - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
On Sat, 8 Jan 2000, Horace Demmink wrote:
On Fri, 7 Jan 2000, Mike Andrews wrote:
An old problem has just come back, but in only one weird case.
I've got a crapload of people getting randomly bumped offline with v.42 or v.42bis related problems. (I suspect v.42bis.)
However... it's only happening on the first 12 channels of ONE DSP card.
I had a similar problem that turned out to be a DSP hardware problem. One of my DSP's would, after moderate use, not answer on the first 12 channels until it was reset. I had flashed several different versions of code, tried different lines (CT1 and PRI), different locations, chassis's, etc. Nothing made a difference. After jerking around with 3COM's RMA dept for a while (you can't RMA it until a tech says it's bad, you can't talk to a tech without a contract) my vendor offered to RMA it for me. I have not seen this symptom pop up on any other cards I have.
Interesting. Any idea what hardware revision the card was? 0.49 maybe? I'm just trying to see if there's any pattern to these at all... Mike Andrews (MA12) * mandrews@dcr.net * http://www.bit0.com/ VP, sysadmin, & network guy, Digital Crescent Inc, Frankfort KY Internet services for Frankfort, Lawrenceburg, Owenton, & Shelbyville "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
On Sun, 9 Jan 2000, Mike Andrews wrote:
Interesting.
Any idea what hardware revision the card was? 0.49 maybe? I'm just trying to see if there's any pattern to these at all...
No idea, I didn't keep record on what revision the card was. It very well could be 0.49 (why are the hardware revisions 0.xx, are these beta release cards? :-) as the others I installed at the same time are. -- Horace Demmink PathWay Computing - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
Hm. So far it seems to be isolated to version 0.49 cards. 3Com? Any insight here? Mike Andrews (MA12) * mandrews@dcr.net * http://www.bit0.com/ VP, sysadmin, & network guy, Digital Crescent Inc, Frankfort KY Internet services for Frankfort, Lawrenceburg, Owenton, Shelbyville "Don't sweat the petty things, and don't pet the sweaty things." On Sun, 9 Jan 2000, Horace Demmink wrote:
On Sun, 9 Jan 2000, Mike Andrews wrote:
Interesting.
Any idea what hardware revision the card was? 0.49 maybe? I'm just trying to see if there's any pattern to these at all...
No idea, I didn't keep record on what revision the card was. It very well could be 0.49 (why are the hardware revisions 0.xx, are these beta release cards? :-) as the others I installed at the same time are.
-- Horace Demmink PathWay Computing
- To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
- To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
WOW! I would definitely get a tech contract. I just burned a DSP card and it started dumping - one call, one shipment, and I had a new DSP card. I would have never considered RMA had it not been for the tech. He told me the dumps were most likely due to the card being bad. I was still screaming at my telco (they earned it before this problem with a list of provisioning different switch types in a single hunt group - u know - standard Telco Crap. I saved myself countless thousands in tech support and lost revenues by not letting customers leave me while I wait to guess the problem. I'd definitely invest in the support contract. Jason A. Nunnelley President of Linkfast Internet Services, Linkfast Inc. 256-739-2008 VOICE CONTACT Linkfast Labs, GPN, MFG, MentionMe Studios, and, the Stupid Project http://www.linkfast.net -----Original Message----- From: owner-usr-tc@lists.xmission.com [mailto:owner-usr-tc@lists.xmission.com]On Behalf Of Horace Demmink Sent: Saturday, January 08, 2000 11:08 AM To: usr-tc@lists.xmission.com Subject: Re: (usr-tc) v.42bis problems On Fri, 7 Jan 2000, Mike Andrews wrote:
An old problem has just come back, but in only one weird case.
I've got a crapload of people getting randomly bumped offline with v.42 or v.42bis related problems. (I suspect v.42bis.)
However... it's only happening on the first 12 channels of ONE DSP card.
I had a similar problem that turned out to be a DSP hardware problem. One of my DSP's would, after moderate use, not answer on the first 12 channels until it was reset. I had flashed several different versions of code, tried different lines (CT1 and PRI), different locations, chassis's, etc. Nothing made a difference. After jerking around with 3COM's RMA dept for a while (you can't RMA it until a tech says it's bad, you can't talk to a tech without a contract) my vendor offered to RMA it for me. I have not seen this symptom pop up on any other cards I have. -- Horace Demmink PathWay Computing - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message. - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
Since noone replied to the first request for info on this I take it 1) noneone else IS messing with these settings or 2)noone HAS been messing with these settings or 3) Everyone simply ignored the mail. So I'll ask once again and then leave it alone on this list. A few revisions back, can't remember how far, the dsp code started to allow setting of the transmiter power levels. This was under line interface options, transmitter level (-db), the same as the quads used to have. They also had the same -11db setting as the quads did. I have had better luck with the quads ( and some old analog multitech modems ) by lowering the power level to -13db. It helped two different problems, disconnects and the long training sessions that never would connect. I was about to start changing these levels to -13db when I noticed that 3com has changed the default setting from -11db to -10db in 2.0.51. In all previuos releases they were set at -11db. Anyone out have any input on this? Does anyone know how to get measurements from the ct1s to determine what the correct level should be? Terry Kennedy OlyPen, Inc. - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
Terry Kennedy wrote:
A few revisions back, can't remember how far, the dsp code started to allow setting of the transmiter power levels. This was under line interface options, transmitter level (-db), the same as the quads used to have. They also had the same -11db setting as the quads did. I have had better luck with the quads ( and some old analog multitech modems ) by lowering the power level to -13db. It helped two different problems, disconnects and the long training sessions that never would connect. I was about to start changing these levels to -13db when I noticed that 3com has changed the default setting from -11db to -10db in 2.0.51. In all previuos releases they were set at -11db. Anyone out have any input on this? Does anyone know how to get measurements from the ct1s to determine what the correct level should be?
I changed our DSP's to -13db when I read the following in the release notes for 2.0.81 <quote> Adjustable Transmit Level Adjustable transmit level provides the ability to configure the modems for optimum performance. Ranges: -3 to -30 dBm for digital T1 line sources. A setting of -13 dBm (S39=13) is recommended for calls over digital lines (T1 or PRI). </quote> We have seen no ill effects from this setting. We had problems with what you describe above, long training sessions that wouldn't connect. I don't know yet if this setting has made an improvement. What I would like to know is why the recommended setting is not the default setting? - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
Thanks for the reply Rob, When I was working with multitech a long time ago on some analog modems made by them, we started playing around for with the power levels in an effort to solve connection problems ( the same long training and then no connect or the dropped connection ) The only explanation I ever got out them was something to do with the way the phone co. provisioned the line and whether or no they added padding to them. Apparently some do some don't. Padding on ct1s is out my experience range so I took their word for it. But there must some way to check this, either a measurement made directly on the line or a indirect method by querying the modems somehow. A 3com tech I tallked to once made reference to reading this info directly off the dsp by plugging in a console cable to them. He never did make it out here on-site, so his knowlege was lost to wind.. Oh well.. -----Original Message----- From: owner-usr-tc@lists.xmission.com [mailto:owner-usr-tc@lists.xmission.com]On Behalf Of Rob Nelson Sent: Sunday, January 09, 2000 11:17 AM To: usr-tc@lists.xmission.com Subject: Re: (usr-tc) Second request --dsp transmitter levels Terry Kennedy wrote:
A few revisions back, can't remember how far, the dsp code started to allow setting of the transmiter power levels. This was under line interface options, transmitter level (-db), the same as the quads used to have. They also had the same -11db setting as the quads did. I have had better luck with the quads ( and some old analog multitech modems ) by lowering the power level to -13db. It helped two different problems, disconnects and the long training sessions that never would connect. I was about to start changing these levels to -13db when I noticed that 3com has changed the default setting from -11db to -10db in 2.0.51. In all previuos releases they were set at -11db. Anyone out have any input on this? Does anyone know how to get measurements from the ct1s to determine what the correct level should be?
I changed our DSP's to -13db when I read the following in the release notes for 2.0.81 <quote> Adjustable Transmit Level Adjustable transmit level provides the ability to configure the modems for optimum performance. Ranges: -3 to -30 dBm for digital T1 line sources. A setting of -13 dBm (S39=13) is recommended for calls over digital lines (T1 or PRI). </quote> We have seen no ill effects from this setting. We had problems with what you describe above, long training sessions that wouldn't connect. I don't know yet if this setting has made an improvement. What I would like to know is why the recommended setting is not the default setting? - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message. - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
participants (5)
-
Horace Demmink -
Jason A. Nunnelley -
Mike Andrews -
Rob Nelson -
Terry Kennedy